Large-scale volcanism on the terrestrial planets

Evidence for mafic volcanism has been found on each planet in the inner Solar System. Lava flows on these planets range in size from 10s to 1000s of kilometers in extent. I investigated large-scale lava flows on Mercury, Earth, and Mars throughout the chapters in this dissertation. Each of these lava flows provides an avenue to study the emplacement and evolution of lava on various planets and under differing conditions, the factors that affect their overall extent, and potential source areas. Chapter One investigates large-scale lava flows in the Cerberus region on Mars, specifically to understand their emplacement history, material properties, and possible magma sources. Mapping and crater counting are used to investigate these flows. The derived absolute age estimates suggest an anomalous trend of decreasing ages with increasing distance from the flow source. Through pi-group scaling, changes to the material properties of the lavas during emplacement are identified as the cause for this decreasing age trend and are attributed to increased strength, and decreased porosity, of the lava. These newly derived absolute age estimates are also used to infer the source of the magma feeding these young and extensive lava flows originated below the Cerberus region. Chapter Two focuses on long and areally extensive lava flows on Earth and Mars, in order to determine the effect of viscosity on the emplacement of 1000+ km flows. In particular, low viscosity lavas are expected to generate such large lava flows. The terrestrial and martian lava flows are interpreted to have been emplaced rapidly, with their final extents limited by the total erupted volume of lava. Through computer modeling, simulations are performed to determine the viscosity values responsible for the observed lava flow extents. The results of this work support low bulk viscosities that correspond to a basaltic composition produce the best reproductions of the martian flows. Chapter Three investigates volcanism on Mercury, which hosts broad smooth plains in three locales, which have varying interpretations for their emplacement, though volcanic processes are favored. The smooth plains units located in the annulus surrounding the Caloris impact basin contain intermingled high-reflectance red and low-reflectance blue plains. Mapping, crater counting, and spectral analyses are used to suggest the emplacement mechanism for these smooth plains. The results of this work support a volcanic origin, though impact related processes cannot be discounted

The Naming Game in Social Networks: Community Formation and Consensus Engineering

We study the dynamics of the Naming Game [Baronchelli et al., (2006) J. Stat. Mech.: Theory Exp. P06014] in empirical social networks. This stylized agent-based model captures essential features of agreement dynamics in a network of autonomous agents, corresponding to the development of shared classification schemes in a network of artificial agents or opinion spreading and social dynamics in social networks. Our study focuses on the impact that communities in the underlying social graphs have on the outcome of the agreement process. We find that networks with strong community structure hinder the system from reaching global agreement; the evolution of the Naming Game in these networks maintains clusters of coexisting opinions indefinitely. Further, we investigate agent-based network strategies to facilitate convergence to global consensus.Comment: The original publication is available at http://www.springerlink.com/content/70370l311m1u0ng3

Madness and the law: The Derrida/Foucault debate revisited

In this article the Derrida/Foucault debate is scrutinised with two closely related aims in mind: (1) reconsidering the way in which Foucault’s texts, and especially the more recently published lectures, should be read; and (2) establishing the relation between law and madness. The article firstly calls for a reading of Foucault which exceeds metaphysics with the security it offers, by taking account of Derrida’s reading of Foucault as well as of the heterogeneity of Foucault’s texts. The article reflects in detail on a text of Derrida on Foucault (‘Cogito and the History of Madness’) as well as a text of Foucault on Blanchot (‘Maurice Blanchot: The Thought from Outside’). The latter text shows that Foucault was at times acutely aware of the difficulty involved in exceeding metaphysics and that he realised the importance in this regard of a reflection on literature. These reflections tie in closely with Foucault’s History of Madness as well as with Derrida’s reflections on literature and on madness. Both Derrida and Foucault contend that law has much to learn from literature in understanding the relation between itself and madness. Literature more specifically points to law’s ‘origin’ in madness. The article contends that a failure to take seriously this origin, also in the reading of Foucault’s lectures, would amount to a denial by law of itself

Systematic review of methods used in meta-analyses where a primary outcome is an adverse or unintended event

addresses: Peninsula College of Medicine and Dentistry, St Luke's Campus, University of Exeter, Exeter, UK. [email protected]: PMCID: PMC3528446types: Journal Article; Research Support, Non-U.S. Gov't© 2012 Warren et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Adverse consequences of medical interventions are a source of concern, but clinical trials may lack power to detect elevated rates of such events, while observational studies have inherent limitations. Meta-analysis allows the combination of individual studies, which can increase power and provide stronger evidence relating to adverse events. However, meta-analysis of adverse events has associated methodological challenges. The aim of this study was to systematically identify and review the methodology used in meta-analyses where a primary outcome is an adverse or unintended event, following a therapeutic intervention

Power and rights in the community: paralegals as leaders in women's legal empowerment in Tanzania

What can an analysis of power in local communities contribute to debates on women’s legal empowerment and the role of paralegals in Africa? Drawing upon theories of power and rights, and research on legal empowerment in African plural legal systems, this article explores the challenges for paralegals in facilitating women’s access to justice in Tanzania, which gave statutory recognition to paralegals in the Legal Aid Act 2017. Land conflicts represent the single-biggest source of local legal disputes in Tanzania and are often embedded in gendered land tenure relations. This article argues that paralegals can be effective actors in women’s legal empowerment where they are able to work as leaders, negotiating power relations and resisting the forms of violence that women encounter as obstacles to justice. Paralegals’ authority will be realised when their role is situated within community leadership structures, confirming their authority while preserving their independence